It's no picnic selling truffles. Yet even when competition is keenest, during peak truffle season, John Magazino manages to place $30,000 a day worth of fungi with the nation's 3- and 4-star restaurants. That makes Magazino one of the biggest truffle dealers in the United States.

Right now, he told ABC News, the season for fresh, black Perigord winter truffles is winding down. He's now selling about $10,000 000 a day of truffles, whereas in January he might have been selling $15,000 a day (at $800 to $1,000 a pound).

The market for still more costly fresh white Alba truffles ($2,000 to $3,000 a pound because of their rarity) peaks in mid-November.

Magazino says his employer, publicly traded Chefs' Warehouse Inc. (Nasdaq: CHEF), sells about $1 billion a year in specialty food products, including truffles. In truffles alone, the New York City distributor is probably the biggest U.S. importer, when combining fresh truffles, preserved truffles and truffle oil, Magazino says.

The business has completely changed, he says, since he first got into it 17 years ago, straight out of Ohio State University. "I got hired as national sales manager by an importer who handled only caviar and truffles,” he said. “It was before anybody else was really in the truffle business."

He no longer sells in person. "Too many people are going door to door," he says.

There's more product on the market, and truffles are consumed in markets where they used to be virtually unknown. He cites Seattle, Portland and Miami as examples. Buyers have a more discriminating eye for quality.

He relies on FedEx and Chef’s Warehouse trucks to deliver his truffles, most of which come from France, Italy and Spain. (His opinion of U.S.-grown truffles is low.)

From the time he gets truffles, Magazino says, every second counts. The price he can charge depends on truffles' weight, which drops 10 percent a day, because of water loss. "That's an exorbitant cost," he says.

Fresh white truffles have to be consumed within five to seven days of being dug out of the ground. "We try to get them within 24 hours of harvest, and to sell them within 24 to 36 hours," he says.

After that, he says, they get soft and lose their aroma. They go bad like "something over-ripe."

Magazino says his relationship with customers is not based on formal contracts. Instead, after years of doing business with a given restaurant, he gets an understanding, he says, of how many pounds of truffles they will need and when.

"We try to estimate as accurately as possible,” he adds. “There's too much risk in our having too many truffles. We'd rather sell out."